Subach, Jim. "Delaware's Natural Wonders." AS PUBLISHED IN THE NEWS JOURNAL (2010): n. pag. Web. 25 Jul 2010.
USGS/NPS Geology in the Parks Website, 2002, Barker, 1997, Collecting Rocks: USGS
General Interest Publication; and USGS The Learning Web Website, 2001
Comp.uark.edu/~sboss/vrockbag.htm
www.scienceclarified.com/landforms
http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/fluvial_systems/geologic_work_of_streams.html
http://www.watersheds.org/earth/valley.htm
http://www.dgs.udel.edu/Geology/Earthquakes/seismicnetwork/bwd.aspx
http://www.dgs.udel.edu/
dsf.chesco.org/water/lib/water/waps/brandywine/brandywine.pdf
Subach, Jim. "Delaware's Natural Wonders." AS PUBLISHED IN THE NEWS JOURNAL (2010): n. pag. Web. 25 Jul 2010.
USGS/NPS Geology in the Parks Website, 2002, Barker, 1997, Collecting Rocks: USGS
General Interest Publication; and USGS The Learning Web Website, 2001